//回顶部
;(function(){
	var obj=document.createElement('div');
		obj.className='backtop';
		obj.id='backtop';
		obj.innerHTML="<i class=\"fa fa-chevron-circle-up fa-2\"></i>";
	obj.onclick=function(){
		window.scroll(0,0)	
	}
	document.body.appendChild(obj);
	window.onscroll=backtop;
	window.onresize=backtop;
	var btop=null
	function backtop(){
		if(btop){clearTimeout(btop)}
		btop=setTimeout(function(){
			if(document.documentElement.scrollTop>100||document.body.scrollTop>100){
				obj.style.display='block'
			}else{
				obj.style.display='none'
			}	
		},120)
	}
})();

console.log("%c", "padding:50px 300px;line-height:120px;background:url('http://ww2.sinaimg.cn/bmiddle/becee87egw1e8citxyyafg20ae059hdt.gif') no-repeat;");
console.log("我就不信你个逗逼懂？");